Active compounds, such as fragrances, but also insect attractants or repellents, as well as some bactericides, are volatile molecules that can only be perceived over a limited period of time. For instance, the perfume industry has a particular interest for compositions or additives which are capable of prolonging or enhancing the perfuming effect of fragrances over a certain period of time, for example in order to overcome the problems encountered when using perfuming ingredients as such, which are too volatile or have a poor substantivity or are only deposited in a small amount onto the surface of the final application. These compositions or additives can be used in various applications, as for example in fine or functional perfumery or in cosmetic preparations. The washing of textiles is a particular field in which there is a constant quest to enable the effect of active substances, in particular perfumes, to be effective for a certain period of time after washing and drying. Indeed, many substances having odors which are particularly suitable for this type of application are known to lack tenacity on laundry, or do not remain on the laundry when rinsed, with the result that their perfuming effect is experienced only briefly and not very intensely. Given the importance of this type of application in the perfume industry, research in this field has been sustained, in particular with the aim of finding new, and more effective solutions to the aforementioned problems.
A variety of chemical delivery systems which release active material by a chemical reaction during or after application (using O2, light, enzymes, water (pH) or temperature as the release trigger) have been described as an alternative to encapsulation systems. In general, due to their inherent instability, the precursors often decompose in the application base during storage and thus release their fragrance raw material before the desired use.
To the best of our knowledge, none of the compositions of the present invention are known from the prior art and no hydrazine derivatives have been described for a use as disclosed further below.
Dynamic libraries using hydrazines and carbonyl derivatives are known from the pharmaceutical industry. However, in such prior art libraries, the ketones or aldehydes are pharmaceutically active compounds, and the libraries themselves are either used to generate a multitude of more or less biologically active compounds or for rapid identifications of biological receptors or ligands. None of the prior art documents suggest, or allow to reasonably expect, that the reversibility of the formation of addition products between carbonyl compounds and hydrazine derivatives may allow to deliver the carbonyl compounds in a controlled manner or that such libraries can be used successfully as perfuming ingredients or even that they allow to prolong the fragrancing effect of a perfuming compound, especially in a consumer product.